How to Remove Mastic Adhesive from Concrete
The easiest way to remove mastic adhesive is by using a concrete grinder. Using boiling water and a scraper is very slow and labor intensive. Even chemical mastic removers will require scraping for many hours. Concrete grinders are relatively easy to use so don’t be scared. Do yourself a favor and rent a concrete grinder from an equipment rental store. Trust me on this I learned the hard way!
How Long Does it take to Remove Mastic Adhesive?
| Mode of Removal | Concrete Grinder | Scrapping with chemical remover | Scrapping with boiling water |
| Hours to remove 200sqft of mastic | 1 | 10 | 20 |
What is Black Mastic Adhesive?
Mastic is the black adhesive that was once used to adhere linoleum, vinyl or tile flooring to the subfloor. This stuff is truly nasty. It has since been replaced with more modern adhesives. It also contains asbestos so inhaling the mastic dust is cancerous. Like most of the cancerous home building products of the 1900s it has been phased out.
Best Mastic Remover for Concrete
The best chemical mastic remover is bean-e-doo. If you want to remove mastic without renting a concrete grinder you will need to use a bean-e-doo to assist in the scraping. This is a good option if you are only removing a little bit of mastic or are cleaning out a tight area where the concrete grinder cant reach. Above is a picture of the scraper I used to remove mastic adhesive. It’s major hard work which is why I recommend the concrete grinder.
How to Remove Mastic Adhesive
Step 1:
Remove flooring and trim to expose the mastic underneath. The mastic will be adhered to either the cement foundation or wood subfloor.
Step 2:
Aquire proper safety equipment before mastic removal. Mastic is cancerous so you don’t want to be breathing in any of the dust. If you take the proper precautions you will be safe. I would recommend a dust mask with a p100 filter. You will want to wear a disposable coverall body suit to protect from getting any particles on your body. Lastly you will want to have goggles to cover your eyes from any dust.
Step 3:
Rent a grinder or sander from your local equipment rental store. Make sure this grinder has a function to suck up dust into a bag. It may also have an exhaust where you can attach a shop vac to suck up the dust. If you have a cement foundation rent a cement grinder with diamond blades. If you have a wood subfloor rent a floor drum sander with multiple sandpaper replacements.
Step 4:
Ventilate the room before starting the sanding by placing a box fan pointing out the window or door. Get an extension cord to allow the grinder space from the outlet.
Step 5:
Turn the grinder or sander on and watch it as it easily remove mastic adhesive from the floor. Move the machine in a continuous motion so that it doesn’t over sand any portion of the floor. Continue the process until the floor is devoid of any mastic and you can clearly see the subfloor or cement.
Step 6:
For areas that cant be reached by the grinder like tight corners, small closets, and some edges you can use a chemical remover and a hand scraper. I recommend bean-e-doo mastic remover for these small areas.
Step 7:
Give the floor and walls a thorough vacuuming to make sure there is no remaining mastic dust. You can also vacuum any other dust collecting surfaces to make sure dust hasn’t collect on those.
Step 8:
Take off coveralls used in sanding and dispose of them. You can also add new P100 filters to your mask as well so you are ready for your next project.
Step 9:
Mop the floor with water and soap solution.
Done
You are ready to start installing your new flooring!
Is Removing Mastic Adhesive Safe?
If you take all the precautions yes it can be safe. Wearing a p100 mask, coveralls and goggles will protect your body from mastic dust. Make sure your sander has a dust collection system to gather the majority of the mastic dust. Open windows and doors and use a box fan to properly ventilate. Vacuum and mop all surfaces removing any remaining contaminants. Dispose of coveralls and mask filters after completion. If you take these measures you will be safe.
Conclusion:
Removing black mastic adhesive is a dirty job but it is much easier when using a machine. I know this because I tried to remove mastic adhesive with a scraper and it was back breaking labor.
More resources: https://blog.onfloor.com/choose-concrete-floor-grinder